Over the past forty years, efforts to improve photovoltaics have taken crystalline silicon nearly to its theoretical limit. Second-generation solar cells using direct gap semiconductors, such as CdTe, have developed to the stage of rivaling silicon. Solution-processing offers an efficient and economically viable route to thin film CdTe-based solar cells. In particular, sintered CdTe thin films deposited from soluble CdTe nanocrystals (NCs) have proven effective as the absorber layer for CdTe solar cells.
Solution-processed solar cells made using roll-to-roll friendly techniques have garnered increasing interest as a low-cost alternative to single crystal silicon or chemical vapor deposited gallium arsenide thin films. A wide variety of materials have been solution processed into photovoltaics, including CdTe. Many of the top solar cell power conversion efficiencies (PCE) have been achieved using spin-coating to produce a uniform semiconductor layer. However, spin-coating has many disadvantages: significant waste of material, mediocre scalability, low throughput, and limited substrate geometries. All of these factors limit the cost reduction, speed of implementation, and flexibility desired from the transformation of new materials strategies into effective technologies.